JPH0561808U - Magnetic recording medium reproducing device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to demagnetize the head by adding a simple circuit to the device without using a special jig. [Structure] A short-circuit switch 26 is provided between both ends of the recording / reproducing head 12A, a recorded magnetic tape 20 is loaded into a set, and a reproducing mode is set.
When the short-circuit switch 26 provided between both ends of the recording / reproducing head 12A is short-circuited in the state of being in contact with 0, the magnetic tape 2
An electromotive force is generated in the recording / reproducing head 12A by the recording magnetization of 0, and an alternating current flows through the recording / reproducing head 12A via the short-circuit switch 26. When the recording magnetization of the magnetic tape 20 gradually becomes signalless, an alternating magnetic field that gradually converges on the recording / reproducing head 12A acts and is demagnetized.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a reproducing device for a magnetic recording medium, and more particularly to a reproducing device for a magnetic recording medium capable of demagnetizing a magnetic head in a tape recorder, a magnetic disk device, a VTR or the like.

[0002]

[Prior Art]

 A tape recorder detects an audio signal by applying a reproducing head (or recording / reproducing head) to a magnetic tape on which an audio signal is magnetically recorded, and magnetically-electrically converting the head, and detects this detection signal and reproduces it. It is designed to be amplified by. In such a tape recorder, the head may be magnetized by inadvertently bringing metal such as a driver close to it, direct current flowing into the head for some reason, or turning the power on / off during operation. There is. Moreover, even when the tape recorder is used for a long time, the head gradually becomes magnetized.

When a recorded tape is reproduced with a magnetized head, the reproduction level is lowered in the middle and high frequencies and the rising of the sound deteriorates. Also, when recording and reproduction is performed with a magnetized recording / reproducing head, the recording frequency decreases from the middle range. The noise component increases over the range. For this reason, it is necessary to demagnetize the magnetic head periodically to prevent the adverse effect of magnetizing.

Conventionally, a head eraser 10 as shown in FIG. 4 is prepared to generate a constant AC magnetic field, and the head 12 is demagnetized by gradually moving away from a state where the head 12 is close to the head 12 of the tape recorder. Alternatively, a cassette type head eraser (not shown) may be loaded instead of the cassette tape, and the set may be set in the reproduction mode to generate an AC magnetic field converging on the cassette type head eraser to demagnetize the head. As shown in FIG. 5, when the degaussing oscillator 14 is connected to the head 12 and the erase key 16 is pressed, the degaussing oscillator 14 is controlled by the microcomputer 18 so that the degaussing oscillator 14 converges. Was passed through the head 12 to generate a converging AC magnetic field to demagnetize the head 12.

[0005]

[Problems to be solved by the device]

 However, in the above-described conventional degaussing method, when degaussing with the head eraser 10 or the cassette type head eraser as shown in FIG. 4, it is necessary to prepare these special jigs, which causes a heavy burden on the user. was there. Further, when the degaussing oscillator 14 provided in the set as shown in FIG. 5 is used for degaussing, the degaussing oscillator 14 has a complicated circuit structure, and thus the burden on the structure is large.

From the above, an object of the present invention is to provide a reproducing apparatus for a magnetic recording medium capable of demagnetizing the head by adding a simple circuit to the apparatus without using a special jig such as a head eraser. Especially.

[0007]

[Means for Solving the Problems]

 SUMMARY OF THE INVENTION In the present invention, the above object is achieved by providing a short-circuit switch between both ends of a magnetic head in a reproducing apparatus for a magnetic recording medium which detects a signal recorded on the magnetic recording medium by the magnetic head.

[0008]

[Action]

 According to the present invention, the magnetic recording medium on which the magnetization is recorded is loaded into the apparatus, the reproducing mode is set, the magnetic head is contacted with the magnetic recording medium, and the short-circuit switch provided between both ends of the magnetic head is short-circuited. Then, due to the recording magnetization of the magnetic recording medium, an electromotive force is generated in the magnetic head, and an alternating current flows through the magnetic head through the short-circuit switch. When the recording magnetization of the magnetic recording medium gradually becomes non-signal, an alternating magnetic field gradually converges on the magnetic head to demagnetize it. Further, even if the recording magnetization does not become a signal, if the reproducing mode is turned off, the magnetic head separates from the magnetic recording medium, so that the magnetic field is demagnetized by the next converging AC magnetic field. As a result, the magnetic head can be easily demagnetized by using an ordinary recorded magnetic recording medium by adding a simple circuit to the device without using a special jig such as a head eraser. it can.

[0009]

【Example】

 FIG. 1 is an overall configuration diagram of a tape recorder according to an embodiment of the present invention.

In the figure, 12 A is a recording / playback recording / playback head, 20 is a magnetic tape, and 22 is a tape tape which is started when the recording mode or playback mode is entered and the recording / playback head is moved from a predetermined standby position. The recording / playback head drives the recording / playback head by amplifying the audio signal in the recording mode when the recording / playback head is pulled away from the magnetic tape to return to the predetermined standby position and the tape running is stopped when the recording / playback head is brought into contact with the recording tape. The recording / reproducing amplifier which amplifies and outputs the detection signal of the recording / reproducing head in the reproducing mode by magnetically recording the magnetic tape, and 26 is a short-circuit switch for short-circuiting both ends of the recording / reproducing head at a predetermined time. Let's use a mechanical switch that can be short-circuited and opened manually. Reference numeral 28 is an operation unit for performing operations such as PLAY, REC, and STOP, and 30 is a microcomputer, which controls a set according to a user operation on the operation unit 28.

When the magnetic tape 20 is loaded into the set with the short-circuit switch 26 set to the b side and opened in advance and the REC operation is performed by the operation unit 28, the microcomputer 30 controls the recording / reproducing amplifier 24. Then, the recording mode is set and the mechanical section 22 is controlled to start the tape running and abut the recording / reproducing head 12A on the magnetic tape 20. The audio signal input from the IN terminal is amplified by the recording / reproducing amplifier and then magnetically recorded on the magnetic tape 20 by the recording / reproducing head 12A. After recording, when a STOP operation is performed by the operation unit 28, the microcomputer 30 controls the mechanical unit 22 to separate the recording / reproducing head 12A from the magnetic tape 20 and stop the tape running.

Further, when the recorded magnetic tape 20 is loaded into the set in a state where the short-circuit switch 26 is opened to the side b in advance and the PLAY operation is performed by the operation unit 28, the microcomputer 30 performs recording / reproduction. The amplifier 24 is controlled to enter the reproduction mode, and the mechanical section 22 is controlled to start the tape running and abut the recording / reproducing head 12A on the magnetic tape 20. The magnetization recording signal of the magnetic tape 20 is detected by the magnetic head 12, amplified by the recording / reproducing amplifier 24, and then output from the OUT terminal to the outside. After the reproduction, when a STOP operation is performed on the operation section 28, the microcomputer 30 controls the mechanical section 22 to separate it from the magnetic tape 20 of the recording / reproducing head 12A and stop the tape running.

On the other hand, when it is desired to demagnetize the recording / reproducing head 12A, a magnetic tape 20 that has been recorded (magnetized and recorded) is loaded in the set in advance, and a PLAY operation is performed on the operation unit 28. Reference numeral 30 controls the mechanical section 22 to start the tape running and bring the recording / reproducing head 12A into contact with the magnetic tape 20. In this state, when the short-circuit switch 26 is set to the side a and the output side of the recording / reproducing head 12A is short-circuited, an electromotive force is generated in the recording / reproducing head 12A due to the recording magnetization of the magnetic tape 20, and the short-circuit switch 26 is operated. An alternating current flows through the recording / reproducing head 12A. When the recording magnetization of the magnetic tape 20 is gradually de-signaled, a gradually converging AC magnetic field acts on the recording / reproducing head 12A and is demagnetized.

Further, even if the recording magnetization does not become a signal, if the STOP operation is performed by the operation section 28, the microcomputer 30 controls the mechanical section 22 to separate it from the magnetic tape 20 of the recording / reproducing head 12A. At the same time, the tape running is stopped. At this time also, the alternating magnetic field gradually converges on the recording / reproducing head 12A to be demagnetized. After degaussing, if the short-circuit switch 26 is set to the b side, normal recording / playback can be performed. During the degaussing operation, since the output side of the recording / reproducing head 12A is in a short-circuited state, no audio signal is output from the OUT terminal.

In this way, by simply adding the short-circuit switch 26 to the set without using a special jig such as a head eraser, the recording / reproducing head can be easily used by using the ordinary recorded magnetic tape 20. Demagnetization of 12 A can be performed. After degaussing the recording / playback head 12A, even if the recorded tape is played back, the playback level does not decrease in the mid-high range and the sound rises well, and even after recording / playing the mid-range to low range is played. The noise component does not increase.

As shown in FIG. 2, an externally controllable short-circuit switch 26A such as a relay switch or a semiconductor switch is provided between both ends on the output side of the recording / reproducing head 12A, and an erase key 32 is added to the operating portion 28A. Then, when the erase key 32 is pressed, the microcomputer 30A sets the set to the reproduction mode, starts the tape running, abuts the recording / reproducing head 12A on the magnetic tape 20, and controls the short-circuit switch 26A. When the erase key 32 is pressed again or a certain time has elapsed after the erase key 32 was pressed first, the microcomputer 30A stops the set and the recording / reproducing head 12A is separated from the magnetic tape 20. At the same time, the tape running is stopped and the short-circuit switch 26A is controlled. Alternatively, the recording / reproducing head 12A may be automatically demagnetized with a single touch by opening the recording / reproducing head 12A.

Further, as shown in FIG. 3, an externally controllable short-circuit switch 26A such as a relay switch or a semiconductor switch is provided between both ends on the output side of the recording / reproducing head 12A, and the short-circuit switch 26A is manually controlled. A switch 34 may be provided so that the short-circuit switch 26A is short-circuited when the control switch 34 is on the a side, and is open when the control switch 34 is on the b-side.

When the recording head and the reproducing head are separated, the reproducing head can be degaussed by providing a short-circuit switch between the output side of the reproducing head. When you play the used tape, you can prevent the playback level from dropping in the mid-high range and improve the sound rise.

Further, although the tape recorder is taken as an example in the above-mentioned embodiment, the present invention is not limited to this, and is similarly applied to a reproducing apparatus for a magnetic recording medium such as a magnetic disk device or a VTR. It is possible.

[0020]

[Effect of the device]

 As described above, according to the present invention, the short-circuit switch is provided between both ends of the magnetic head, the magnetic recording medium on which the magnetization is recorded is loaded into the apparatus, the reproducing mode is set, and the magnetic head is applied to the magnetic recording medium. When the short-circuit switch provided between both ends of the head is set to the short-circuited state, the recording magnetization of the magnetic recording medium generates an electromotive force in the magnetic head, and an alternating current flows through the magnetic head through the short-circuiting switch, causing magnetic recording. When the recording magnetization of the medium is gradually de-signaled, the magnetic head is demagnetized due to the gradually converging AC magnetic field, and even if the recording magnetization is not de-signaled, if the reproducing mode is turned off, the magnetic head becomes magnetic. Since the magnetic head is separated from the recording medium, the magnetic field is gradually defocused by the converging AC magnetic field, so that the device can be easily demagnetized without using a special jig such as a head eraser. Simply wipe the circuit, using conventional recorded magnetic recording medium, easily it can be carried out demagnetization of the magnetic head.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a tape recorder according to an embodiment of the present invention.

FIG. 2 is a partially omitted configuration diagram of a tape recorder according to a modification of the present invention.

FIG. 3 is a partially omitted configuration diagram of a tape recorder according to another modification of the present invention.

FIG. 4 is an explanatory diagram showing an example of a conventional head degaussing method.

FIG. 5 is an explanatory diagram showing another example of a conventional head degaussing method.

FIG. 6 is a waveform diagram showing an output current waveform of the degaussing oscillator in FIG.

[Explanation of symbols]

 12A Recording / playback head 24 Recording / playback amplifier 26, 26A Short-circuit switch 30, 30A Microcomputer

Claims (1)

[Scope of utility model registration request] 1. A reproducing apparatus of a magnetic recording medium for detecting a signal recorded on a magnetic recording medium by a magnetic head, wherein a short-circuit switch is provided between both ends of the magnetic head. apparatus.